Factored out crates for web version

mandelia_native/src/main.rs

@@ -0,0 +1,17 @@
+fn main() -> eframe::Result {
+    // mandelia::main()
+
+    let options = eframe::NativeOptions {
+        ..eframe::NativeOptions::default()
+    };
+
+    eframe::run_native(
+        "Mandelia",
+        options,
+        Box::new(|cc| {
+            Ok(Box::new(mandelia_ui::App::new(cc)))
+        })
+    )
+}
+
+// this is backend-independent